If you're familiar with Regedit, it's relatively easy to get rid of extra stuff. Once the registry is clean, delete the folder(s). Just be careful and make sure you have a good backup before proceeding.
There are tons of Gigabyte items in the registry in various places include HKEY_CLASSES_ROOT, LOCAL_MACHINE, CURRENT_USER... Some of it is obviously part of the mobo Gigabyte stuff I installed but some isn't so obvious.
Hmm... I'll have to consider how much this is really bugging me.